Over half of all women of child-bearing age are overweight or obese, and maternal obesity increases the risk of developing gestational diabetes mellitus (GDM), which is found in 2-5% of pregnancies in the United States. Children born from pregnancies complicated by maternal obesity and/or GDM are at increased risk themselves for chronic obesity and metabolic health problems such as insulin resistance. African American (AA) children are at particular risk given the high prevalence of obesity among AA women (70% of AA women of child-bearing age are overweight or obese), and the comorbidity between obesity and GDM. The intrauterine environment provides a mechanism through which obesity and diabetes risk may be transmitted from mother to child. The proposed research aims to investigate the independent and interactive effects of maternal obesity and of GDM on the body composition and metabolic health of AA children. We hypothesize that children exposed to an obesogenic and/or diabetic intrauterine environment will have more body fat, greater insulin secretion and lower insulin sensitivity, dyslipidemia, increased cytokine levels, and reduced satiety hormone levels. We will recruit AA women for whom information is available regarding their glucose tolerance during pregnancy, and seek permission to enroll their 5-8 year-old children in our study. Children will be grouped according to their mothers'weight (obese vs. normal weight) and GDM (GDM or non-GDM) status during pregnancy. During an inpatient clinical research center visit to ensure controlled food intake conditions, children's body composition will be assessed by dual-energy x-ray absorptiometry (DXA), their blood lipid, cytokine, and satiety hormone profiles will be obtained, and their insulin sensitivity, secretion and clearance assessed via a mixed-meal tolerance test. In addition, we will measure children's physical activity via accelerometers, and their dietary intake via three 24-hour recalls, to determine whether any between group differences in these variables contribute to differences in body composition and metabolic health. By gaining an understanding of the independent and interactive effects of maternal obesity and of GDM on pediatric health, we can better identify the population at greatest risk for chronic health problems before they develop, and may be able to elucidate mechanisms to overcome the adverse effects of prenatal exposure to obesity and/or GDM. Relevance: Ultimately, this and subsequent related research will yield information regarding the manner in which obesity and diabetes risk are transmitted, and will identify nutritional and environmental interventions to inhibit the epigenetic transmission of obesity and metabolic disease.